Propulsion conveyer



June 10,1930; E, HOFFMANN 1,763,307

PROPULS ION CONVEYER Filed Dec. 14, 192? 3 Sheets-Sheet l 5 Jnventor bym 7wr A horney June 10, 1930. E. HOFFMANN 1,763,307

PROPULSION CONVEYER Filed Des. 14, 1927 3 Sheets-Sheet 2 5 Fig.2

E 2 Jnventor Attorney June 10, 1930. E. HOFFMA'NN 1,763,307

PROPULSION CONVEYER 3 Sheets-Sheet 5 Filed Dec.- 14, 1927 ulnvenior- Attorney Patented June 10, 1930 ERNST HOFFMANN, 0F SALZA, NEAR THE HARZ, GERMANY, ASSIGNOR TO SCHMIDT,

KRANZ & C0. NORDHA'U'SER MASGHINENFABRIK AKTIEH-GESELLSCHAFT, NORD- HAI l'SER NEAR THE 'HARZ, fl-ERMANY rRoruLsIoiv convnynn Application filed December 14, 1927, Serial No.- 239,847, and in Germany December 15, 1926.

My invention relates to improvements in propulsion conveyers and one of the objects of the improvements is to provide an improved conveyer of the type in which reciprocating movement is imparted to the trough, "table, or other support by means of a pair of meshing elliptical gear wheels rotatably supported at one of the foci. Thereby the movement imparted to the support is firstgradually accelerated during the forward stroke and rapidly retarded at the end of the forward stroke, so that during the first part of the forward movement of the support the material is carried along by friction and accelerated, while it overcomes friction by inertia during the rapid retardation of the support and continues its forward movement during the return stroke of the support.

The acceleration of the support during the first part of the forward stroke must not exceed a certain maximum in "order to insure that the material will be carried along. If the friction of the material on the support is small the acceleration must be. reduced. In my improved mechanism such retardation is obtained by connectingthe driven elliptical'gear wheel with the support at points more or less'away from the major axis of the ellipse. Thereby the maximum velocity of the support during the forward stroke is reduced, and further the time taken for the for- \v'ard stroke is made greater than the duration of the return stroke, both facts reducing the acceleration. With this new arrangement an unsymmetrical curve will be obtained in a diagram illustrating the varying velocity of the support during a complete cycle consisting of forward stroke and return stroke.

Preferably the driving mechanism is constructed so that the support can be connected at will to different parts of the driven elliptical gear wheel, so that the said mechanism can be adapted to different conditions,and more particularly to the quality of the material to be conveyed or the inclination of the support.

The point of connection between the support and the driven elliptical gear wheel can be changed to such a position that while the driving mechanism is kept rotating in the same direction, the direction of the conveying movement will be reversed.

In constructions heretofore proposed elastic means have been elliptical gear wheel and the support, in order to avoid the transmission of heavy jars from the support to the driving mechanism. If in constructions of this type too much material falls on the support it may happen that the load is such that the support is not reciprocated any more, but becomes stationary, the rotary movement of the driving mechanism being taken up by the elastic connection between the same and the support. In such cases it is necessary to remove the material from the support by hand. In my improved construction meansare provided for limiting the, elasticity of the connection provided between the elliptical gear wheel and the gutter. This will insure that even when the support is overloaded acertain amount of re" ciprocating movement will be imparted thereto, so that the material is gradually conveyed forwardly, and the overload is taken from the support.

provided between the driven When mounting the driving mechanism for example in mines it may happen that the standards by means of which the said mechanism is supported on the floor of the gallery transmit the pressure of the rock to the base frame of themechanism, which is therefore pressed on the floor and deformed, so that the parts of the mechanism connecting the same to the base frame are broken. To overcome this drawback, in my improved conveyer the driving mechanism is secured to the base frame at two points only, and with its bottom part above the bottom part of the said base frame, so that the base frame can be deformed without exerting any stress on the driving mechanism.

For the purpose of explainingthe invention an example embodying the same has been shown in the accompanying drawings in which the samev reference characters have been used in all the viewsto indicatecorresponding parts. In saiddrawings,

ig. 1 is a somewhat diagrammatical elevation showing my improved conveyer,

Fig. 2 is a diagram of velocities of the sup port corresponding to the position of the crank pin on the major axisof the driven elliptical gear wheel, which position has been shown in Fig. 1 in dotted lines,

Figs. 3 and 4 are similar diagrams showing the velocities of my improved conveyer corresponding to two different positions of the crank pin,

Fig. 5 is an elevation showing'theconveyor and its driving mechanism,

Fig. 6 is an elevation showing the casing enclosing the drivingmechanism and illustrating the manner of mounting the same on abase frame,

Fig. 7 is a plan view taken on the line 77 of Fig. 5 with the top portion of the apparatus removed,

Fig. 8 is a detail view showing the crank pin and the manner of mounting the same on the shaft carrying the driven elliptical gear wheel,

gig. 9 is a side elevational view of Fig. 8, an

Fig. 10 is a detail View partly in section showing the connecting rod and its spring.

Referring at first to the diagrammatical View illustrated in Fig. 1, my improved propulsion conveyer comprises a support 1. elliptical gear wheels '2 and 3 having like pitch lines, a connecting rod 1 connecting the driven gear wheel 2 with the support 1, and driving means for the elliptical gear wheel 3 com'-' prising a gear wheel 5 and a pinion 6 mount ed on a shaft 12. The shafts 7 and 8 of the elliptical gear wheels pass through like foci of the ellipses. When the crank pin to which the connecting rod; is connected is located at a point on the major axis of the gear wheel 2, as is shown at gin-Fig. 1 in dotted lines, the diagram of velocities of the support will be s mmetrical for the forward and'return stro' es thereof, as is shown in Fig. 2. When rotating the gear wheel 2 from the position shown in Fig. l in the direction of the arrow :1: the movement is first slowly accelerated from the point a of the diagram, corresponding to the position of the crank pin shown at 9 in Fig. 1, to the point I), and the movement is thereafter rapidly retarded to the point 0, at which the gear wheel 2 has been turned through an angle of 180. The support 1 then begins its return stroke, the velocity being first rapidly increased to-the point (1, whereupon it is gradually reduced to zero, when the crank pin is again in the position shown at 9 in Fig. 1, corresponding to the point a of the diagram.

During the first part of the forward stroke of the support corresponding to the section 11-1; of the diagram the velocity must be such that the material is carried along by the support. Thereafter the motion of the support is rapidly retarded according to the section b 0 of the diagram, so that the material,

by its inertia, will slide forward on said support. While the material is moving for wardly the support is retracted, its return movement, corresponding to the section c(.l of the diagram, being first rapidly accelerated and thereafter gradually retarded according to the section d--a. Thus the material is conveyed forwardly in the direction of the arrow y'shown in Figs. 1 and 2.

If the friction of the material on the support is very small, it may happen that the support will not carry along the said material when moying through the part of its forward stroke represented by the section a-b of the diagram. support on the part of the stroke corresponding to thesection a-b must be reduced. For

this purpose the crank pin is disposed a suitable distance away from the major axis of the wheel 2, for instance at the point 9 shown in Fig. 1, so that the major axis 9-7 and the line 7 9 include a certain angle o. By placing the crank pin at a point off the major axis of the Wheel 2 the diagram of velocities is changed as is indicated by the examples illustrated in Figs. 3 and 4, the diagram shown in Fig. 3 corresponding to'an-angle m=22 and the diagram shown in Fig. 4 corresponding to an angle m=45 (see Fig. 9). As will appear from the said (imgrams, the acceleration during the forward stroke of the support represented by the sections ab and a'.b" is considerably reduced as compared to the acceleration shown 'n Fig. 2, first, because the maximum velocity epresented by the points I) and b is smaller than the maximum velocity represented by the point I), andv second, because the period of time t, or t, of the forward stroke is considerably greater than the period of time t or t of the return stroke. By comparing Figs. 2, 3 and 4 it will be found that the maximum velocity b and b I time t, and t," differ in Fig. 4 to a greater degree than in Fig. 3 from the corresponding values 6 and 1., respectively of Fig. 2. Thus the acceleration can be adapted to varying conditions, and more particularly to the friction of the material on the support and the position of the said support relatively to the horizontal, which support may be horizontal or inclined downwardly toward one end or Therefore the acceleration of the.

also

and the period of the other. \Vhen the angle 0; is 180 or over For adapting the operating mechanism at to various conditions I prefer to any time construct the gear wheel 2, the crank shaft .7 and crank pin 9 so that the said, crank pin can positionby means of a nut 28,

- connected loosely .with the stud 20 of the other,

As shown,

be set at different positions relatively to the major axis of the elliptical gear 2. Thus the same mechanism can he used in connection with supports disposed horizontally or inclined downwardly'toward one end or the and the position of the crank pin can be altered at any time accordingto the character of the material to be conveyed, so as to set said pin in the most effective position. Further, the crank pin can be secured to the gear wheel at an angle w=180 or over, for reversing the direction of-the movement of the material without reversing the driving mechanism.

In Figs. 5, 6, and 7 I have illustrated the I construction of the operating mechanism and the manner of mounting the same on a frame.

the shafts 7 and 8 carrying the elliptical gear wheels 2 and 3 respectively and the shaft 12 carrying the pinion 6 are mounted in a casing comprising a bottom part 10 and aremovable top part 11. To the shaft 12 a pulley or other driving member 13 is keyed. To the outer end of the shaft 7 the crank pin 9 is secured. In the constructionshownthe,

crank pint) is made integral with or fixed to a disk 14 secured to a disk 15 made integral with or fixed to the shaft 7. As will appear more particularly from Figs. 8 and 9, the disk 15 is providedwith a large number of screw holes 16 disposed in an annular series thecenter of which is upon the axis of, the shaft, so that the disk 14 may be securedv to the disk 15 by means of screws 17 with the crankpin 9" in different to the major axis of the center of said wheel 2 and on either side of the elliptical gear wheel. l

The connecting rod 4 is associated with a spring 18 permitting such rod to yield lengthwise in case of an excessive load, in order to prevent the transmission of heavy iarrs to the driving mechanisn'l. The arrangement of the said spring has been shown in detail in Fig. 10. On the crank pin 9 a bearing block 19 is mounted which is made integral with a stud 20 formed with a socket 2.1. By means of rods 22 a cross-head'23 is secured rigidly to the block 19, such cross-head being formed with a bore 24. In bushings 25 and 26 of the socket 21 and the bore respectively the connecting rod 4 is guided so as tobe axially slidable therein. To one end of the said connecting rod is screwed or otherwise secured rigidly a disk 27, which is held in and which is block 19 by means of bolts 29 provided with ruts 39, sufficient play being left between said uuts'and the stud 20 to permit a limited relative movement of the parts 27 and 19 to the extent indicated in Fig. 10 by the letter 9] The coiled spring 18 interposed between the cross-head 23 and the disk 27 tends to force the rod 4 inwardly and into the position 9 and the support 1.

positions relatively\ shown in Fig. 10. The power of the said spring is such that the mechanism is capable of yielding within certain limits in case of excessive load, the extent of the compression of the spring 18 being limited by the bolts 29 and nuts 30. Thus. if the support is overloaded by too much material falling thereon the power is elastically transmitted to the said support. But after a certain amount of compression the spring will undergo no further compression, owing to'the nuts 30 coming in contact with the adjoining face of, the flange on the stud 20, so that from that moment on the connecting rod 4 will be practically rigid with said stud, so as to effect a positive connection between the crank Thus the said support will be given a slight reciprocating motion even in case of a very heavy load. Ihax'e found that if the compression of the spring is not limited the operating mechanism will be rotated in case of an excessive load without imparting any movement to the support 1, the spring 18 being compressed the full length of its stroke, and that in such cases it is necessary to remove the excess of material from the support by hand. which rcquires much time. But by positively con-' necting the operating mechanism with the support after the spring has been compressed to apredeterminedextent, the support will be reciprocated for gradually renuwing the excess of material, though under normal conditions the operation is elastic by reason of the spring 18 and excessive strain on the perating mechanism is avoided.

Figs. 5 and 6 show the manner of mounting the frame 10,- 11 on a base frame supported for example on standards. As will appear from these figures, the casing 10. ll

is mounted in such a manner that it can not touch the bottom of the gallery in case of deformation of the base frame. which.

would expose the casing 10, 11 to excessive strain. The base frame comprises a pair of channel irons32. connected at their ends by. channel irons 33 (Fig. 7) by means of two bolts 34 permitting a certain play of the casing 10 relatively'to the channel irons 32, and the bottom part of the casing 10 is located at a higher level than the bottom part of the channel irons 32. Thus, in case of deforma- 7 tion of the framework the channel irons 32 may be pressed on the ground and bent therei by in the manner indicated in Fig. 6. But such bending is notl transmitted to the casing 10.

While in describing the invention refer ence has been made to a particular example embodying the same I wish it to be understood that my invention is not limited to the construction shown in the drawings, and that various changes may be made in the general-- arrangement of the apparatus and the construction of its parts without departing from the invention.

I claim:

1. A propulsion conveyer, comprising an elongated conveying support mounted for being reciprocated in longitudinal direction, an operating mechanism comprising a pair of meshing elliptical gear wheels each rotatably supported at one of its foci, means to connect said conveying support with one of said gear, wheels at different angular distances from the major axis of the ellipse of such gear wheel, and means to rotate the other one of said gear wheels.

2. A propulsion co-nveyer, comprising a conveying support mounted for being reciprocated in longitudinal direction, an operating mechanism comprising a pair of meshing elliptical gear wheels each rotatably supported at one of its foci, means to connect said conveying support with one of said gear wheels at different angular distances from the major axis of the ellipse of such gear wheel, within a range extending to about 180, and means to rotate the other one of said gear wheels.

3. A propulsion conveyer, comprising a conveying support mounted for being reciprocated in longitudinal direction, an operating mechanism connected with said conveying support and comprising a pair of meshing elliptical gear wheels, an adjustable disk, a crank pin on such disk, means for connecting such disk with one of said gear wheels to bring the crank pin into different pesisl tions relatively to the major axis of such elliptical gear Wheel, a connecting rod connecting said crank pin and conveying snpport, and means to rotate the other one of said gear wheels.

4. A propulsion conveyer, comprising a conveying support, mechanism for imparting reciprocating movement to said support, a frame on which said mechanism is mounted, and a yieldable base frame on which said frame is yieldingly mounted.

. 5. A conveyer comprising a conveying support arranged for reciprocating motion, a driving mechanism including a pair of meshing elliptical gear wheels,and an operative connection between one of said wheels and said support, the said connection being adjustable as to its point of actuation by such gear wheel, which point may be set at different angular distances from the major axis of the ellipse of such gear wheel.

6. A coriveyer comprising a conveying support arran ed for reciprocating motion, a driving mec anism including a pair of meshing elliptical gear wheels, and an operative connection between one of said wheels and said support, the said connection including a crank pin secured to said wheel adjustably, toset such pin in any one of a plurality of positions equidistant from the axis about which said wheel is mounted to rotate.

7. A conveyer comprising a conveying support arranged for reciprocating motion, a driving mechanism including a pair of meshing elhptical gear wheels, and an operative connection between one of said wheels and said support, the said connection including a disk connected with said wheel rigidly, another disk adjacent to the first-mentioned disk, securing members connecting said disks, one of the said disks having portions for the reception of said securing members which portions are disposed in an annular series the center of which is upon the axis of rotation of said wheel, to permit of a circumferential adjustment of said second disk relatively to the first, and a crank pin carried by said second disk and operatively connected with said support.

In testimony whereof I hereunto affix my signature.

ERNST HOFFMANN. 

